docs: def __check_logging_rules(configuration):
      """ Check that the logging values are proper """
      valid_log_levels = [
          'debug',
          'info',
          'warning',
          'error'
      ]
      if configuration['logging']['log_level'].lower() not in valid_log_levels:
          print('Log level must be one of {0}'.format(
              ', '.join(valid_log_levels)))
          sys.exit(1)